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477 lines
11 KiB
477 lines
11 KiB
// SIP Message Library
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package sip
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import (
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"bytes"
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"net"
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"strconv"
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)
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type Headers map[string]string
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// Msg represents a SIP message. This can either be a request or a response.
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// These fields are never nil unless otherwise specified.
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type Msg struct {
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// Fields that aren't headers.
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VersionMajor uint8
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VersionMinor uint8
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Method string // Indicates type of request (if request)
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Request *URI // dest URI (nil if response)
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Status int // Indicates happiness of response (if response)
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Phrase string // Explains happiness of response (if response)
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Payload Payload // Stuff that comes after two line breaks
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// Special non-SIP fields.
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SourceAddr *net.UDPAddr // Set by transport layer as received address.
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// Important headers should be further up in the struct.
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From *Addr // Logical sender of message
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To *Addr // Logical destination of message
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Via *Via // Linked list of agents traversed (must have one)
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Route *Addr // Used for goose routing and loose routing
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RecordRoute *Addr // Used for loose routing
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Contact *Addr // Where we send response packets or nil
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CallID []byte // Identifies call from INVITE to BYE; never empty, only absent
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CSeq int // Counter for network packet ordering
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CSeqMethod string // Helps with matching to orig message
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MaxForwards int // 0 has context specific meaning
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UserAgent []byte // Name of the SIP stack
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// All the other RFC 3261 headers in plus some extras.
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//
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// These byte slices will be nil if absent, in which case the header never
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// appeared. If they are empty, then the header did appear, but without a
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// value.
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Accept []byte
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AcceptContact []byte
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AcceptEncoding []byte
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AcceptLanguage []byte
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AlertInfo []byte
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Allow []byte
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AllowEvents []byte
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AuthenticationInfo []byte
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Authorization []byte
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CallInfo []byte
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ContentDisposition []byte
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ContentEncoding []byte
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ContentLanguage []byte
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Date []byte
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ErrorInfo []byte
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Event []byte
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Expires int // Seconds registration should expire.
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InReplyTo []byte
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MIMEVersion []byte
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MinExpires int // Registrars need this when responding
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Organization []byte
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PAssertedIdentity *Addr // P-Asserted-Identity or nil (used for PSTN ANI)
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Priority []byte
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ProxyAuthenticate []byte
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ProxyAuthorization []byte
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ProxyRequire []byte
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ReferTo []byte
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ReferredBy []byte
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RemotePartyID *Addr // Evil twin of P-Asserted-Identity.
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ReplyTo []byte
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Require []byte
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RetryAfter []byte
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Server []byte
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Subject []byte
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Supported []byte
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Timestamp []byte
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Unsupported []byte
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WWWAuthenticate []byte
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Warning []byte
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// Extension headers.
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Headers Headers
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}
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//go:generate ragel -Z -G2 -o msg_parse.go msg_parse.rl
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func (msg *Msg) IsResponse() bool {
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return msg.Status > 0
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}
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func (msg *Msg) String() string {
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var b bytes.Buffer
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msg.Append(&b)
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return b.String()
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}
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func (msg *Msg) Copy() *Msg {
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if msg == nil {
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return nil
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}
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res := new(Msg)
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*res = *msg
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res.Request = msg.Request.Copy()
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res.To = msg.To.Copy()
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res.From = msg.From.Copy()
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res.Via = msg.Via.Copy()
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res.PAssertedIdentity = msg.PAssertedIdentity.Copy()
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res.RemotePartyID = msg.RemotePartyID.Copy()
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res.Route = msg.Route.Copy()
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res.Contact = msg.Contact.Copy()
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res.RecordRoute = msg.RecordRoute.Copy()
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res.Headers = make(Headers, len(msg.Headers))
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for k, v := range msg.Headers {
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res.Headers[k] = v
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}
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return res
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}
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// I turn a SIP message back into a packet.
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func (msg *Msg) Append(b *bytes.Buffer) {
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if msg == nil {
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return
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}
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if !msg.IsResponse() {
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if msg.Method == "" {
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b.WriteString("INVITE ")
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} else {
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b.WriteString(msg.Method)
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b.WriteString(" ")
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}
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if msg.Request == nil {
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// In case of bugs, keep calm and DDOS NASA.
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b.WriteString("sip:www.nasa.gov:80")
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} else {
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msg.Request.Append(b)
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}
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b.WriteString(" ")
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msg.appendVersion(b)
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b.WriteString("\r\n")
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} else {
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msg.appendVersion(b)
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b.WriteString(" ")
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b.WriteString(strconv.Itoa(msg.Status))
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b.WriteString(" ")
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if msg.Phrase == "" {
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b.WriteString(Phrase(msg.Status))
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} else {
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b.WriteString(msg.Phrase)
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}
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b.WriteString("\r\n")
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}
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b.WriteString("From: ")
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msg.From.Append(b)
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b.WriteString("\r\n")
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b.WriteString("To: ")
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msg.To.Append(b)
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b.WriteString("\r\n")
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for viap := msg.Via; viap != nil; viap = viap.Next {
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b.WriteString("Via: ")
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viap.Append(b)
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b.WriteString("\r\n")
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}
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if msg.Route != nil {
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b.WriteString("Route: ")
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msg.Route.Append(b)
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b.WriteString("\r\n")
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}
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if msg.RecordRoute != nil {
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b.WriteString("Record-Route: ")
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msg.RecordRoute.Append(b)
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b.WriteString("\r\n")
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}
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if msg.Contact != nil {
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b.WriteString("Contact: ")
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msg.Contact.Append(b)
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b.WriteString("\r\n")
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}
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b.WriteString("Call-ID: ")
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b.Write(msg.CallID)
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b.WriteString("\r\n")
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b.WriteString("CSeq: ")
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b.WriteString(strconv.Itoa(msg.CSeq))
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b.WriteString(" ")
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b.WriteString(msg.CSeqMethod)
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b.WriteString("\r\n")
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if msg.UserAgent != nil {
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b.WriteString("User-Agent: ")
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b.Write(msg.UserAgent)
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b.WriteString("\r\n")
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}
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if !msg.IsResponse() {
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if msg.MaxForwards == 0 {
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b.WriteString("Max-Forwards: 70\r\n")
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} else {
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b.WriteString("Max-Forwards: ")
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b.WriteString(strconv.Itoa(msg.MaxForwards))
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b.WriteString("\r\n")
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}
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}
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if msg.Accept != nil {
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b.WriteString("Accept: ")
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b.Write(msg.Accept)
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b.WriteString("\r\n")
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}
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if msg.AcceptEncoding != nil {
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b.WriteString("Accept-Encoding: ")
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b.Write(msg.AcceptEncoding)
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b.WriteString("\r\n")
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}
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if msg.AcceptLanguage != nil {
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b.WriteString("Accept-Language: ")
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b.Write(msg.AcceptLanguage)
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b.WriteString("\r\n")
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}
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if msg.AlertInfo != nil {
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b.WriteString("Alert-Info: ")
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b.Write(msg.AlertInfo)
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b.WriteString("\r\n")
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}
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if msg.Allow != nil {
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b.WriteString("Allow: ")
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b.Write(msg.Allow)
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b.WriteString("\r\n")
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}
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if msg.AllowEvents != nil {
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b.WriteString("Allow-Events: ")
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b.Write(msg.AllowEvents)
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b.WriteString("\r\n")
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}
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if msg.AuthenticationInfo != nil {
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b.WriteString("Authentication-Info: ")
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b.Write(msg.AuthenticationInfo)
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b.WriteString("\r\n")
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}
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if msg.Authorization != nil {
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b.WriteString("Authorization: ")
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b.Write(msg.Authorization)
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b.WriteString("\r\n")
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}
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if msg.CallInfo != nil {
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b.WriteString("Call-Info: ")
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b.Write(msg.CallInfo)
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b.WriteString("\r\n")
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}
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if msg.ContentDisposition != nil {
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b.WriteString("Content-Disposition: ")
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b.Write(msg.ContentDisposition)
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b.WriteString("\r\n")
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}
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if msg.ContentEncoding != nil {
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b.WriteString("Content-Encoding: ")
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b.Write(msg.ContentEncoding)
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b.WriteString("\r\n")
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}
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if msg.ContentLanguage != nil {
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b.WriteString("Content-Language: ")
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b.Write(msg.ContentLanguage)
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b.WriteString("\r\n")
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}
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if msg.Date != nil {
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b.WriteString("Date: ")
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b.Write(msg.Date)
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b.WriteString("\r\n")
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}
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if msg.ErrorInfo != nil {
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b.WriteString("Error-Info: ")
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b.Write(msg.ErrorInfo)
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b.WriteString("\r\n")
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}
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if msg.Event != nil {
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b.WriteString("Event: ")
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b.Write(msg.Event)
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b.WriteString("\r\n")
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}
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// Expires is allowed to be 0 for for REGISTER stuff.
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if msg.Expires > 0 || msg.Method == "REGISTER" || msg.CSeqMethod == "REGISTER" {
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b.WriteString("Expires: ")
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b.WriteString(strconv.Itoa(msg.Expires))
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b.WriteString("\r\n")
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}
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if msg.InReplyTo != nil {
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b.WriteString("In-Reply-To: ")
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b.Write(msg.InReplyTo)
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b.WriteString("\r\n")
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}
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if msg.MIMEVersion != nil {
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b.WriteString("MIME-Version: ")
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b.Write(msg.MIMEVersion)
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b.WriteString("\r\n")
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}
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if msg.MinExpires > 0 {
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b.WriteString("Min-Expires: ")
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b.WriteString(strconv.Itoa(msg.MinExpires))
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b.WriteString("\r\n")
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}
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if msg.Organization != nil {
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b.WriteString("Organization: ")
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b.Write(msg.Organization)
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b.WriteString("\r\n")
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}
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if msg.PAssertedIdentity != nil {
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b.WriteString("P-Asserted-Identity: ")
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msg.PAssertedIdentity.Append(b)
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b.WriteString("\r\n")
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}
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if msg.Priority != nil {
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b.WriteString("Priority: ")
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b.Write(msg.Priority)
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b.WriteString("\r\n")
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}
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if msg.ProxyAuthenticate != nil {
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b.WriteString("Proxy-Authenticate: ")
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b.Write(msg.ProxyAuthenticate)
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b.WriteString("\r\n")
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}
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if msg.ProxyAuthorization != nil {
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b.WriteString("Proxy-Authorization: ")
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b.Write(msg.ProxyAuthorization)
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b.WriteString("\r\n")
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}
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if msg.ProxyRequire != nil {
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b.WriteString("Proxy-Require: ")
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b.Write(msg.ProxyRequire)
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b.WriteString("\r\n")
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}
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if msg.ReferTo != nil {
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b.WriteString("Refer-To: ")
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b.Write(msg.ReferTo)
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b.WriteString("\r\n")
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}
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if msg.ReferredBy != nil {
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b.WriteString("Referred-By: ")
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b.Write(msg.ReferredBy)
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b.WriteString("\r\n")
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}
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if msg.RemotePartyID != nil {
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b.WriteString("Remote-Party-ID: ")
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msg.RemotePartyID.Append(b)
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b.WriteString("\r\n")
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}
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if msg.ReplyTo != nil {
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b.WriteString("Reply-To: ")
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b.Write(msg.ReplyTo)
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b.WriteString("\r\n")
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}
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if msg.Require != nil {
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b.WriteString("Require: ")
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b.Write(msg.Require)
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b.WriteString("\r\n")
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}
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if msg.RetryAfter != nil {
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b.WriteString("RetryAfter: ")
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b.Write(msg.RetryAfter)
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b.WriteString("\r\n")
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}
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if msg.Server != nil {
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b.WriteString("Server: ")
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b.Write(msg.Server)
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b.WriteString("\r\n")
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}
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if msg.Subject != nil {
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b.WriteString("Subject: ")
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b.Write(msg.Subject)
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b.WriteString("\r\n")
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}
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if msg.Supported != nil {
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b.WriteString("Supported: ")
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b.Write(msg.Supported)
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b.WriteString("\r\n")
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}
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if msg.Timestamp != nil {
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b.WriteString("Timestamp: ")
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b.Write(msg.Timestamp)
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b.WriteString("\r\n")
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}
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if msg.Unsupported != nil {
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b.WriteString("Unsupported: ")
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b.Write(msg.Unsupported)
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b.WriteString("\r\n")
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}
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if msg.Warning != nil {
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b.WriteString("Warning: ")
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b.Write(msg.Warning)
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b.WriteString("\r\n")
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}
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if msg.WWWAuthenticate != nil {
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b.WriteString("WWW-Authenticate: ")
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b.Write(msg.WWWAuthenticate)
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b.WriteString("\r\n")
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}
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if msg.Headers != nil {
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for k, v := range msg.Headers {
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b.WriteString(k)
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b.WriteString(": ")
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b.WriteString(v)
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b.WriteString("\r\n")
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}
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}
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if msg.Payload != nil {
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b.WriteString("Content-Type: ")
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b.WriteString(msg.Payload.ContentType())
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b.WriteString("\r\n")
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payload := msg.Payload.Data()
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b.WriteString("Content-Length: ")
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b.WriteString(strconv.Itoa(len(payload)))
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b.WriteString("\r\n\r\n")
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b.Write(payload)
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} else {
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b.WriteString("Content-Length: 0\r\n\r\n")
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}
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}
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func (msg *Msg) appendVersion(b *bytes.Buffer) {
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b.WriteString("SIP/")
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if msg.VersionMajor == 0 {
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b.WriteString("2.0")
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} else {
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b.WriteString(strconv.FormatUint(uint64(msg.VersionMajor), 10))
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b.WriteString(".")
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b.WriteString(strconv.FormatUint(uint64(msg.VersionMinor), 10))
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}
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}
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